Relationship between lymphocyte DNA fragmentation and dose of iron oxide (Fe2O3) and silicon oxide (SiO2) nanoparticles.

At present, the use of nanoparticles is a controversial topic, especially when analyzing their effects in human tissues. Nanoparticles (NPs) can cause oxidative stress by increasing membrane lipids peroxidation and reactive oxygen species, and decreasing intracellular glutathione. Oxidative stress plays an important role in cell signaling and inflammatory responses. It can result in genotoxicity, affect cell proliferation, and induce DNA damage. The objective of this study is to evaluate the genotoxic potential of NPs in lymphocyte DNA. Wistar female rats (N = 45) were sorted in three randomized groups as follows: Group 1 (N = 20); Group 2 (N = 20) and a control group (N = 5). A single dose of iron oxide (Fe2O3) and silicon oxide (SiO2) NPs dissolved in saline solution were administered orally to the rats. Cardiac puncture was performed to extract peripheral blood for genotoxic analysis. DNA fragmentation for lymphocytes was performed. Control rats showed a fragmentation percentage of 11.20 ± 2.16%. Rats exposed to SiO2 and Fe2O3 NPs for 24 h showed statistically significant differences in DNA fragmentation percentages as compared with that of the control group. A lineal dose-response correlation between genotoxic damage and exposure to SiO2 and Fe2O3 NPs was found (r2 = 0.99 and 0.98 for SiO2 and Fe2O3, respectively). In conclusion, we found that exposure to Fe2O3 and SiO2 NPs can cause DNA fragmentation in lymphocytes in a dose-dependent manner.

THE FIRST TWENTY YEARS (1994-2014) OF OZONE SOUNDINGS FROM RAPA NUI (27°S, 109°W, 51 M A.S.L.).

Ozone (O3) soundings have been performed on Easter Island or Rapa Nui (27°S, 23 109°W, 51 m a.s.l.) since 1994 as part of the Global Atmospheric Watch (GAW) Programme of the World Meteorological Organization (WMO). In this work, we analyze 260 soundings compiled over the period 1994-2014, and make the data available for the international community. We characterize O3 profiles over this remote area of the Pacific by means of statistical analyses that consider, on the one hand, a traditional climatology that describes the data in terms of seasonal cycles based on monthly averages and, on the other hand, a process oriented analysis based on self-organizing maps. Our analyses show the influence of both tropical and subtropical/mid-latitude air masses at Rapa Nui. The former occurs in summer and fall when convective conditions prevail, and the latter in late winter and spring when subsiding conditions are recurrent. The occurrence of stratospheric intrusions in late winter and spring in connection with deep troughs and the presence of the subtropical jet stream is also apparent in the data set. The tropospheric ozone column is in good agreement with the corresponding data derived from satellites but with a systematic overestimate of summer and fall values. We show evidence of an upward trend in ozone near the surface, which suggests the impact of local pollution. We look forward to an enhancement of the Rapa Nui observing site, given its location that offers a privileged position to observe climate change over the sparsely sampled and vast South Pacific Ocean.

The prevalence of BRCA1 and BRCA2 mutations among young Mexican women with triple-negative breast cancer.

Various guidelines recommend that women with triple-negative breast cancer should be tested for BRCA1 mutations, but the prevalence of mutations may vary with ethnic group and with geographic region, and the optimal cutoff age for testing has not been established. We estimated the frequencies of BRCA1 and BRCA2 (BRCA) mutations among 190 women with triple-negative breast cancer, unselected for family history, diagnosed at age 50 or less at a single hospital in Mexico City. Patients were screened for 115 recurrent BRCA mutations, which have been reported previously in women of Hispanic origin, including a common large rearrangement Mexican founder mutation (BRCA1 ex9-12del). A BRCA mutation was detected in 44 of 190 patients with triple-negative breast cancer (23 %). Forty-three mutations were found in BRCA1 and one mutation was found in BRCA2. Seven different mutations accounted for 39 patients (89 % of the total mutations). The Mexican founder mutation (BRCA1 ex9-12del) was found 18 times and accounted for 41 % of all mutations detected. There is a high prevalence of BRCA1 mutations among young triple-negative breast cancer patients in Mexico. Women with triple-negative breast cancer in Mexico should be screened for mutations in BRCA1.

Influence of hard vs. soft ground surfaces on bone accretion in prepubertal footballers.

Information regarding osteogenic effects of physical activity performed on different playing surfaces is scarce. A total of 42 children (9.2±0.2 years, Tanner stages I-II) participated in this study. 14 were playing on artificial turf soft ground (SG), 14 on a natural non-grass hard ground (HG) and 14 were assigned to the sedentary control group (C). Whole body and hip scans (dual energy X-ray absorptiometry), anthropometric variables (weight and height) and physical fitness (VO2max) were determined in all participants. Bone mineral content (BMC) values were higher in the SG group compared to the C group at the legs (209.75±5.11 g vs. 187.42±5.14 g, respectively), pelvis (122.72±4.27 g vs. 98.58±4.29 g respectively) and whole-body level (1 126.1±22.81 g vs. 1 035.34±22.92 g, respectively). The hard ground (HG) group also showed higher values in the majority of BMC variables compared to the C group. Additionally, bone mineral density (BMD) was significantly higher at all sites of the hip in both active groups compared to control (P<0.05). No differences between HG and SG were found. In summary, similar bone mass accretion is obtained by prepubescent footballers independently of the surface on which they practice football.

Chylous ascites after retroperitoneal aortocava lymphadenectomy for endometrial cancer: a case report.

This is a case report of chylous ascites after retroperitoneal aortocava lymphadenectomy for endometrial cancer. There are few reports of chylous ascites in gynecologic surgery. Treatment is primarily conservative. The present case was resolved with a low fat diet with medium-chain triglyceride (MCT) supplements and somatostatin IV.

Animal model of corneal ectasia in rabbits by intrastromal injection of type II collagenase.

INTRODUCTION: Collagenase II has been used to induce experimental keratoconus in animal models. However, its effect when administered by intrastromal injection has not been studied, so the purpose of this study was to study the effects of intrastromal injection of collagenase II on corneal surface and corneal morphology. METHODS: Six New Zealand rabbits were used, collagenase II was administered by intrastromal injection (5µL of 2.5mg/mL) in the right eyes and balanced salt solution in the left eyes. Keratometry was performed to evaluate curvature alteration, also at day 7 corneas were obtained and Hematoxylin-Eosin staining was performed to examine morphologic changes. Likewise, changes in type I collagen expression were investigated by Sirius Red staining and semiquantitative PCR. RESULTS: K1, K2 and Km presented differences in the means with statistically significant changes. The morphological changes that were demonstrated were degradation and irregular arrangement of the corneal stroma, increase in the cellular density of keratocytes and slight cellular infiltration. Finally, it was demonstrated that there is greater expression of type I collagen fibers in the experimental group as opposed to the controls and the thickness of the fibers also increased due to the action of collagenase II, however, in terms of genetics there were no changes in the expression of type I collagen at molecular level between the control and experimental groups. CONCLUSIONS: Collagenase II administered by intrastromal injection is able to induce changes in the corneal surface and stroma, being able to simulate a model of keratoconus.

Characteristics and impacts of peer assisted learning in university studies in health science: A systematic review.

OBJECTIVE: Systematically analyse the characteristics and impact of peer assisted learning programmes implemented in undergraduate health education. METHODS: Following the PRISMA protocol, we searched the electronic indexed databases WoS and SCOPUS; original studies reporting peer assisted learning in health science careers were included in the systematic review. Among them, the studies between 2010 and January 2020 were selected, and information regarding programme structures and principal results was subsequently extracted. RESULTS: A total of 47 studies were included in the review. The most frequent programme characteristics were the near-peer teaching modality, lecture classes, clinical laboratories and peer tutor training. The main findings identified were benefits in tutors' confidence and knowledge, better student comprehension and a more comfortable learning environment in comparison with that established by academic tutors. CONCLUSION: Peer assisted learning programmes have shown qualitative benefits in the learning environment, generation of support networks and confidence in knowledge acquired. Nonetheless, quantitative benefits measured as improvements in marks are inconclusive. Future studies are needed to standardise the methodologies used to determine which characteristics are the most positive in the learning process.

Toxic effects of inhaled manganese on the olfactory bulb: an ultrastructural approach in mice.

Olfactory dysfunction is a common symptom reported by patients with neurodegenerative disorders such as Alzheimer's and Parkinson's diseases. Despite the knowledge gathered about the pathology of these diseases, little information has been generated regarding the ultrastructure modifications of the granule cells that regulate the information for odor identification. Swollen organelles and nuclear invaginations identified the exposed mice. Necrosis was evidenced at 4th week of exposure, whereas apoptosis arose at 8th week of exposure. A ruffled electron-dense membrane changes were also found. The changes observed could be explained by the reactive oxygen species generated by manganese and its effects on the membrane's structure and on the cytoskeleton's function. This study contributes to correlate metal air pollution and neurodegenerative changes with olfactory affection.

Development of appropriateness criteria for hip arthroscopy in patients with femoroacetabular impingement. / Desarrollo de criterios de uso adecuado para la artroscopia de cadera en pacientes con choque femoroacetabular.

INTRODUCTION: The use of hip arthroscopy as a treatment for femoroacetabular impingement (FAI) has increased exponentially in recent years without robust evidence or consensus about the patients who benefit from it. OBJECTIVE: To develop explicit criteria for the appropriate indication of hip arthroscopy in FAI. METHOD: A panel of experts was formed with 11 traumatologists following the RAND/UCLA method to identify the appropriateness criteria for hip arthroscopy in patients with FAI. The panel made independent evaluations of each indication using a nine-point adequacy scale, then met face-to-face to vote using an iterative discussion process. The influence of the variables on the final score was studied using multinomial logistic regression models. The Classification and Regression Tree (CART) analysis was used to summarize the results in the form of decision trees. RESULTS: Twenty-three point four percent of the 192 scenarios evaluated in the face-to-face meeting was considered appropriate (40% agreement), 26.6% uncertain and 50% inappropriate (75% agreement). The most influential variables in considering the use of arthroscopy appropriate were: joint symptoms compatible with shock test, duration of symptoms, functionality, age and Hip Outcome Score (HOS) scale. CONCLUSIONS: We developed an explicit set of criteria for the appropriate use of hip arthroscopy in FAI using the RAND/UCLA method, providing a tool that would identify patients who are potential candidates for surgical treatment using arthroscopic hip surgery.

Intervenciones de prevención y tratamiento en recién nacidos con defectos del tubo neural / Prevention and treatment interventions in newborns with neural tube defects

Introducción: los defectos de tubo neural son anomalías congénitas del sistema nervioso central; estas malformaciones elevan el grado de morbimortalidad en los recién nacidos durante los diez primeros años de vida. Objetivo: definir las intervenciones que el profesional de enfermería puede realizar en el recién nacido con defectos del tubo neural tomando en cuenta aspectos de prevención y tratamiento. Material y métodos: se realizó una búsqueda sistematizada en las bases de datos de PudMed y BVS de julio-septiembre 2021, que incluyo artículos completos relacionados con intervenciones de enfermería a recién nacidos con defectos del tubo neural publicados entre 2016-2021 y artículos médicos de revisión literaria. Resultados: se seleccionaron 41 artículos para definir las intervenciones, a saber: a. intervenciones preventivas con el consumo de ácido fólico, control prenatal y educación sanitaria, b. intervenciones relacionadas al tratamiento enfocadas al cuidado de las derivaciones ventriculoperitoneales y cuidado de heridas quirúrgicas, c. intervenciones ante complicaciones. Discusión: las tasas de mortalidad y discapacidad infantil han incrementado en los últimos años a pesar de los avances en la medicina preventiva, por lo que toma relevancia el consumo de ácido fólico, educación sanitaria y métodos de cuidado hospitalarios. Conclusiones: la enfermera neonatal puede participar con cuidados estandarizados en beneficio de los recién nacidos considerando intervenciones para evitar retraso en el crecimiento y desarrollo de los hitos motores y cognitivos, reducir complicaciones y mejorar las posibilidades de una óptima condición de vida.

Introduction: neural tube defects are congenital anomalies of the central nervous system; These malformations increase the degree of morbidity and mortality in newborns during the first ten years of life. Objective: define the interventions that the nursing professional can be carried out in newborns with neural tube defects, considering aspects of prevention and treatment. Material and methods: systematized search was carried out in the databases of PudMed and BVS during July-September 2021, which included complete articles related to nursing interventions for newborns with neural tube defects published between 2016-2021 and medical literature review articles. Results: forty-one articles were selected to define the interventions: a. Preventive interventions in the consumption of folic acid, prenatal control and health education, b. Interventions related to treatment focused on the care of ventriculoperitoneal shunt and surgical wound care, c. interventions for complications. Discussion: infant mortality and disability rates have increased in recent years despite advances in preventive medicine, which is why the consumption of folic acid, health education and hospital care methods are relevant. Conclusions: neonatal nurse can participate with standardized care for the benefit of newborns, considering interventions to avoid delayed growth and development of motor and cognitive milestones, reduce complications and improve the chances of an optimal life condition.

Higher bone mass in prepubertal and peripubertal female footballers.

OBJECTIVES: The main aim of this study was to compare the bone mass of female football players with controls of different pubertal stages. METHODS: Sixty five girls aged 8-14 years (10.14 ± 0.1, Tanner stages I-IV) participated in the study. Twenty participants were prepubertal (10 prepubertal control) and 45 peripubertal (15 peripubertal control). All footballers trained two days per week while the control group did not perform regular physical activity outside of school. Body composition was assessed by Dual-energy X-ray absorptiometry. Analysis of covariance was performed to evaluate differences in lean and bone masses. RESULTS: Significant differences in lower-body extremities lean mass (LLM) between peripubertal groups were found (P < .05). Additionally, prepubertal footballers showed higher values of bone mineral content (BMC) at the femoral neck (P < .05) while peripubertal footballers exhibited enhanced BMC at the whole-body, trochanter and Wards triangle area. Bone mineral density (BMD) was higher in footballers compared to their non-active peers at the femoral neck and intertrochanter (P < .05, respectively) while in the peripubertal footballers higher BMD values were found in almost all of the studied body sites. CONCLUSION: Female footballers showed higher bone and lean masses compared to control counterparts; these differences are already detectable at prepubertal ages and more consistent after pubertal spurt.

[Macronutrients intake in school teenagers in Soria capital]. / Ingesta de macronutrientes en adolescentes escolarizados en Soria capital.

OBJECTIVES: To study the macronutrients intake in Soria teenagers from 10 to 19 years, as well as their body mass index (BMI). METHODS: A seven-day diet questionnaire filled in by an accidental sample of teenagers (54 boys and 56 girls) from public schools in the capital. Working out the average daily intake of energy, carbohydrates, lipids and proteins by the software of "Alimentación y Salud" which also gives values of individual recommended dietary allowances (RDAs) related to each individual's particular characteristics. Use of Student's t-test to compare the average values of the estimated intakes of different nutrients and their RDAs. RESULTS: In general, the intakes of energy, proteins and lipids are statistically significant over the RDAs, while the carbohydrates intake is under the recommendations. With reference to the type of lipids, the intake is over the RDAs for cholesterol, monounsaturated fatty acids, and saturated fatty acids, but not for polyunsaturated fatty acids. Among girls from 13 years of age more than 12% have a higher BMI than 26 kg/m2, but between 10 and 12 years of age more than 20% of the students have this parameter under 16 kg/m2. CONCLUSIONS: According to the results, it would be useful to implement some nutritional intervention among the adolescents in Soria capital to promote a healthy feeding in order to avoid possible disorders (obesity, anorexia, etc.).

Targeted over-expression of FGF in chick embryos induces formation of ectopic neural cells.

Fibroblast growth factors (FGFs) are known to be involved mainly in mesoderm formation in Xenopus embryos but their participation in other inductive mechanisms such as neural induction has not been clearly established and is now under study. Here, we provide evidence that targeted over-expression of members of this family of growth factors in the periphery of full-length primitive streak chick embryos produces the formation of ectopic neural cells that are able to differentiate into neurons. The supernumerary neural plate obtained derives from the epiblast layer of the blastoderm and show signs of neural differentiation 24 h after the application of FGF. We have used cell labeling and have examined the expression of mesodermal markers to ascertain how this expansion of the neural forming region of the epiblast takes place. We conclude that the new neural cells formed are originated in the region of the epiblast fated to be epithelia and that the induction of the ectopic neural tissue is not mediated by an increase, migration or new formation of axial mesoderm. This strongly suggests that FGF is acting directly on epiblast cells, changing their fate from epidermal ectoderm to neural ectoderm. Therefore, our results show that FGF can induce neural ectoderm when acting on still uncommitted cells and, therefore, it is a putative candidate for acting in normal neural induction during development.

Modulation of CYP1A2 enzyme activity by indoleamines: inhibition by serotonin and tryptamine.

Recent evidence supports a role for the CYP2D6 enzyme in the metabolism of tryptamine. Because of the partial overlapping between substrate and inhibitor specificities that characterize some cytochrome P450 enzymes, these finding raise the possibility that other cytochrome P450 enzymes may be modulated by endogenous compounds. In the present study, the occurrence of modulatory effect of 17 neurotransmitters, precursors and metabolites on the cytochrome P450 1A2 (CYP1A2) enzyme activity was studied in human liver microsomes. Two indoleamines, serotonin and tryptamine, showed a competitive inhibitory effect on the high-affinity component of the phenacetin O-de-ethylase activity. Both substances induced an inhibition of 100% of the activity, with Ki values of 35 and 45 microns for serotonin and tryptamine, respectively. The inhibitors did not affect the microsomal NADPH-reductase activity. Other substances, which were either poor or partial inhibitors, were dopamine, L-tyrosine, tryptophol, 5-hydroxytryptophol, adrenaline, indole-3-acetaldehyde, 5-hydroxytryptophan, noradrenaline, vanillylmandelic acid, indole-3-acetic acid, dihydroxyphenylacetic acid, and homovanillic acid. L-tryptophan, dihydroxyphenylalanine and 5-hyroxyindole acetic acid induced very low or no inhibitory effect. Tryptamine and serotonin metabolism in human liver microsomes was studied after inhibition of monoamine oxidase activity with the unspecific MAO inhibitor pargyline. Both serotonin and tryptamine were metabolized in human liver microsomes. However, the metabolism of both indoleamines was not significantly inhibited with the CYP1A2-specific inhibitor furafylline, thus indicating that the inhibition of CYP1A2 was not related to metabolic activity of the CYP1A2 enzyme on serotonin or tryptamine. The CYP1A2 enzyme is expressed in brain and is involved in the metabolism of psychoactive drugs. Therefore, the fact that endogenous compounds could modulate the CYP1A2 activity suggests that local activity of brain CYP1A2 might be susceptible to local regulatory mechanisms. This may have important clinical implications, one of them being that CYP1A2 activity in brain tissue might correlate poorly with that of liver, as observed in vivo. In addition, the influence of indoleamines on CYP1A2 activity might be partly responsible for a number of associations of CYP1A2 activity with nutritional and environmental factors.

Cell death in suboptic necrotic centers of chick embryo diencephalon and their topographic relationship with the earliest optic fiber fascicles.

The structural features of suboptic necrotic centers (SONCs) in the floor of the chick embryo diencephalon were studied. These necrotic areas were observed lateral to the prospective zone of the optic chiasm through developmental stages 14 to 24. The relationship between SONCs and the earliest optic fiber fascicles also was studied in an attempt to determine the possible significance of these cell death areas in the mechanism of optic pathway development. In SONCs, healthy neuroepithelial cells contain primary lysosomes and phagocytose fragments of dead cells. Discrete regions within the cytoplasm of some cells show electron-transparent vacuoles in contact with dense contents of ruptured lytic bodies. The cytoplasm of dying cells and dead cell fragments are notably electron dense, with numerous secondary lysosomes and electron-transparent vacuoles. These observations are interpreted on the assumption that after autophagic processes, condensation and fragmentation take place in dying cells of the SONCs. In the ventricular lumen adjacent to the SONCs, numerous more or less spherical bodies are observed that appear to be shed from the tip of the cells constituting the SONCs. Three different types of intraventricular bodies can be distinguished: loose, moderately dense, and highly dense. The first type appears to originate from apical portions of cells that undergo autolytic processes. Moderately dense fragments are interpreted as originating from dying cells in which the cytoplasm is undergoing condensation. Finally, highly dense intraventricular bodies appear to be fragments of dead cells that are shed into the ventricular lumen. SONCs separate the prospective area of the optic chiasm from lateral regions of the diencephalic floor. Extracellular spaces are poorly developed within the wall of the SONCs, whereas the neuroepithelium of the presumptive optic chiasm and regions located rostral and caudal to SONCs show abundant and extensive extracellular spaces. These are bounded by long marginal processes of neuroepithelial cells. Sagittal sections of embryonic heads at stages 22-24 reveal optic fiber fascicles penetrating the SONCs asymmetrically, as they are found only in its caudal half. These observations suggest that the SONCs function as doorways made of compact neuroepithelium, to be traversed by the earliest optic fibers before they reach the middle zone of the floor of the diencephalon through which they travel to the contralateral optic tract within large extracellular spaces.

Cell proliferation during early development of the chick embryo otic anlage: quantitative comparison of migratory and nonmigratory regions of the otic epithelium.

During development of the otic anlage, a certain proportion of epithelial cells migrate toward the mesenchymal compartment to form part of the acoustic-vestibular ganglion. The migrating cells are observed only in the zone of the otic anlage that will make contact with the acoustic-vestibular ganglion (so-called ganglion zone). In Hamburger and Hamilton's stages 13 to 16, the number of epithelial cells that migrate is relatively low, but it becomes steadily higher from stage 17 on. In the otic anlage of chick embryos, between developmental stages 9 and 21 (48 to 94 hours of incubation), mitotic index, apical or basal localization within the epithelium of dividing cells, and orientation of the mitotic spindles were analyzed. These features in the ganglion zone were compared with observations in the rest of the otic epithelium, where migratory processes do not take place. In stages 13 to 15, when few epithelial cells are migrating, the mitotic index (MI) in the ganglion zone of the otic anlage is similar to that in nonmigratory regions. In more advanced stages, however, when cell migration becomes accelerated, the MI in the migratory zone of the otic wall is significantly higher than that in the rest of the otic epithelium. This suggests an intimate relationship between the migration of otic epithelial cells and a high rate of cell proliferation, the possible nature of which is discussed. Although the majority of mitoses in the otic anlage are located at the apical surface of the epithelium, from stage 13 onward, a few dividing cells are seen in the basal third of the epithelium. Furthermore, these basal mitoses appear exclusively in the migratory zone of the otic anlage, thus suggesting a possible relationship between epithelial cell migration and basal mitosis. During the developmental period prior to stage 18, no significant differences in mitotic spindle orientation are noted between migratory and nonmigratory zones of the otic anlage. In contrast, in stages of maximal otic epithelial cell migration (stages 19 to 21), the frequency of mitoses with the spindle axis oriented radially is significantly higher in the migratory zone. These findings point toward a close correlation between increased frequency of radial mitotic spindle orientation and intense cell migration, although the exact nature of this relationship is as yet unknown.

Fragile X syndrome: discordant levels of CGG repeat mosaicism in two brothers.

Fragile X syndrome is associated with an unstable repeated CGG trinucleotide sequence in the 5' untranslated region of the FMR-1 gene. A significant number of individuals with a mild or atypical presentation are mosaics for the CGG expansion. We report a family with two brothers. The proband had severe mental retardation as well as most of the Fragile X syndrome stigmata, whereas his brother shows only mild learning difficulties. Both inherited a 80 x CGG trinucleotide premutation from the mother. They were negative for the FRAXA fragile site in over 100 metaphases examined. Flanking markers verified that both had inherited the same FMR-1 allele and Xq27-q28 flanking sequences from the mother. The methylation status of the brothers indicated active FMR-1 transcription as determined by using StB12.3/EcoRI + Eagl blots. CGG size or methylation mosaicism was not apparent from Southern blots. Polymerase chain reaction and chemiluminescent detection identified that both brothers had different degrees of mosaicism for the CGG expansion. Large expansions amounting to 70% of the total were visible in the proband, whereas less than 5% of the signal was larger than the premutation in his mildly affected brother. These findings suggest that mosaicism may be responsible for some of the variation in penetrance in this disorder.

Effect of iron and estrogen on melatonin secretion by the chicken pineal gland.

Estrogen effects on pineal secretion of melatonin are controversial. Some feel that estrogen inhibits melatonin output in vitro but not in vivo. Melatonin levels vary with the age in chickens where circulating estrogen levels also vary. Laying hens have minimal melatonin levels and maximal serum iron concentrations. Thus, we reasoned that iron released by estrogen may inhibit melatonin secretion from the chick pineal gland. The present study shows that perifusion of estrogen-treated chick pineal glands with several concentrations of iron greatly inhibited melatonin secretion.

A neural plate fate map at stage HH4 in the chick: methodology and preliminary data.

This paper centers on the design of a perfected methodology for establishing a fate map of the chick neural plate at stages 3d/4, projected upon the closing neural tube (stages 9-11). The principal aim was to saturate the area of interest with overlapping small isochronic and homotopic grafts (100-300 cells), in order to later derive firmer conclusions from the detailed comparisons thus made possible. We used an ocular grid centered on Hensen's node for the localization of the grafts. Chick embryos in New culture were used as donors and hosts, to evade potential differences in intercalation or proliferation behavior between quail and chick cells. Donor tissue was labelled with the non-diffusing fluorescein derivative carboxyfluorescein diacetate succinimidyl ester, later visualized by fluorescence microscopy at various timepoints during survival and by a sensitive whole-mount immunocytochemical protocol after fixation. We present only preliminary data of the ongoing mapping, illustrating well-delimited patches of graft-derived cells which can be identified across the neural/non-neural epiblast continuum, or across the dorsoventral dimension of the neural tube wall.

Displacement of rifampicin bound to serum proteins by addition of levamisole.

We have studied, by ultrafiltration, the interactions between rifampicin (15 and 30 microM) and levamisole (7 microM) since both drugs may be associated for the treatment of brucellosis. We can observe a statistically significant increase in the free plasmatic fraction of rifampicin at the studied concentration of levamisole, which indicated that levamisole reduced rifampicin bound to proteins (290 and 250%, respectively).